Carburetor for internal combustion engines



Dec. 15, 1936. B. H. RAVANELLI 2,064,217

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed guns 6, 19:53- 4 v 2 Sheets-Sheet 1 I I I I N K: N g I I N '0 as Q T Q Q l i $99 9 R r g g 0 L.- (\l 0 I I 3H m k.

3 w w J N INVENTOR.

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed June 6, 1933 2 Sheets-Sheet 2 INVENTOR. 4mm- Patented Dec 15, 1936 omens-r012. ron INTERNAL conmus'rloiv ENGINES Ben 11. Ravanelli, Austin, Tex.

Application June s, 1933, SerialNo. 674,474

'lClaims.

To fully explain the advantages of my invention I shall refer briefly to the operation of well known types of carburetors. The objects 15 of all designs. are to give a properly proportionedmixture under different conditionsand all de-. pend-on air velocity and vacuum, which are controlled by athrottle valve or other means, for operation. The vacuum caused by air flowing 20 through-Venturi or restricted openings aspirates fuel through an orifice which is placed in these openings or near them; the orifice size 'may be controlled but the quantity of fuel aspirated depends on the flow of air primarilyand not on 25 the'pressure of the fuel. Most carburetors have a float chamber in which the fuel is kept at a certain level by a valve operated by the float. The fuel is supplied to the float-chamber by a low pressure pump or other means; the float 30 valve allows only enough fuel to enter to keep the float at a certain level and thus replace the fuel aspirated or used. In some carburetors the mixture of air and fuel is heated by the heat of the exhaust manifold.

35 With the-foregoing in view, this invention op.-

' crates on the, well known principles that fuel will not form explosive mixtures unless well mixed in proper proportion with oxygen or air, that a fuel will be well atomized, thereby help- 40 ing mixing with air, when injected by pressure through a small orifice, that the volatility of a fuel depends on. its temperature, and that Venturi and restricted openings oifer resistanceto- 45 This invention provides a means independent of suction or air velocity to supply fuel to the air stream caused by suction of a piston in the tled except with low power output and starting 55 ofthe engine. This positive control of the atomized fuel, properly proportions the fuel and air mixture, improves acceleration. as the inertia of fuel is decreased by forcing it, makes cold starting easy as atomization helps the fuel to vaporize, eliminatesrestrictions and Venturl openings thus increasing the volumetric, thermal, and overall efliciencies, is ideal .for aircraft engines as it will function in any position, allows supercharging as the fuel quantity will simply be increased to take care of the increased. air supply, is easily adjusted for altitude, eliminates part of the noise of suction and allows use of non-volatile as well as volatile fuels due to the vaporization caused by atomization.

Supplementing the advantages afforded by the control member or positive 'control,. those derived from heating the fuel by exhaust gas, cooling water, or electricity while under positivecontrol. j Due to the high speclflcheatand latentheat of liquid fuels a large quantity of heat which would be lost by the engine can be, conserved by the fuel and used to heat "the charge. The principle of this arrangement is to injectfuel which vaporizes instantly into. cool air and f therebyadmit to the engine a maximum percentage of oxygen for perfect combustion. Fuels with low volatility (kerosene and fuel oil) can be'used as they will be sufficiently vaporized to form explosive mixtures with air. Higher compression ratios can be used with last mentioned fuels thusincreasing the efficiency.

A special means has been provided which is of .such design that when an intermittently operating fuel pump is used to feedfuel to the fuel the carburetor and the excess fuel will be bypassed, thereby controlling the peak pressure.

These last mentioned means have been com- 40 bined with the other instrumentalities of' this. invention, all of which will now be described in detail. My carburetor is not to be limitedto the form shown, as my invention, as defined in theappended claims, may be embodied in a plurality of forms. Referring now to the accompanying drawings in which:

Figure 1 is a general view in side elevation of an internal combustion engine havin the invention applied thereto showing a means of heating the fuel, a means-to control the temperature of the fuel, a means of supplying the .fuel, and the we fuel and throttle controls. I

Figure 2 is a cross sectional view of a plunger pump for supplying high pressure fuel. '55

Figure 3 is across sectional view in side elevation of afuel heating device. Figure 4 is a cross sectional view in side eleva tion of the carburetor showing the control memher, orifice control, and means to control the flow.

Figure 5 is a cross section taken on the line A-A showing the control member.

and regulator.

Figure 6 is a detafl view showing the orifice vention is applied willsufiice since it can be made applicable to many different types.

The body I, Figure l, of the carburetor is attached by screws to the intake manifold 2, which is attached to the engine 3. To the body I is attached the power control rod 4, which if pushed or pulled turns the control member lever 5, carrying the control member 6, and throttle valve lever 8, carrying throttle valve shaft 9, and throttle valve I0, Figure 2. The motion of control member lever 5, is transmitted to throttle valve lever 8 by means of link I. The levers 8 and 5 are so proportioned that the movement of 8- is about twice that'of 5 and that 8 is at the end of its travel when 5 has covered only about one half of its travel. As these levers control the throttle valve shaft 9, carrying throttle valve I 0, and control member 6, the movements of these elements (throttle valve and control member), only, will be referred to hereinafter as the proportioning of the levers 5 and 8 are not a part of this, invention.

The fuel comes from tank I2, through fuel line I3, into filter or receptacle I4, through fuel line I5, into high pressure pump I6. The, pump I 6 is attached by bolts to the engine 3 and is actuated by cam .I I which is operated by the engine 3, and in this case is the valve camshaft. The fuel is pumped through fuel line I8 into heat container I9. The heat container I9 is part of a casting 48 which is intermediate to the exhaust manifold 20 and exhaust pipe 2I. The heat, in this case, is supplied by the exhaust gas, coming from the exhaust manifold 28. The quantity of exhaust gas, shunted through the heat container I 9, and the temperature of the fuel therein, is controlled by the rod 22, manually or automatically operated, which is attached to the valve lever 23, carrying link 24 and valve lever 25; the

' valve levers 23 and 25 carry valves 25 and 21,

Figure 3, which open and close simultaneously.

The heating device is not essential but is a means providing positive vaporization of the fuel.

The fuel passes from the heat container I 9, through the fuel line I8, into the carburetor body I. The control member 8 determines. the quantity of this fuel that is injected through the orifice II, Figure 4, into the air stream in the intake manifold 2. Due to leakage and a bypass, there The plunger 29, Figure 2, of the pump I6 is held against the face of the cam IT, by means of spring 38, which is supported by the pump body at one end and a removable retainer plate 3 I which fits in an annular groove in the plunger 29, at the other. .The plunger 29, of'the pump I 6, is actuated by the cam II, which is operated by the engine 3. On the downstroke of the plunger 29 fuel is sucked from the fuel line I5, through fitting 32 and intake valve 33, which is held against its seat in the fitting 32, by the spring 34. The plunger 29 sucks in a quantity of fuel, which is about equal to its displacement, represented by the dotted line and top of plunger 29. -On the upstroke of the plunger 29, the fuel sucked in is discharged through the discharge valve 35, which is held against its seat 36 by spring 31 held by fitting 38, into fittings 38, 39, and fuel line I8.

The pump I 6 is shown as a plunger pump with a a constant discharge for a certain speed of the cam H. The discharge does not have to .be constant and could be varied by manipulating either the intake or discharge valve, by varying V the stroke of the pump, or by other'means. Although I have shown a plunger type pump for discharging the fuel under pressure, it is to beclearly understood that the invention is not to be so limited as any suitable means for building up a pressure can be used. Any such means would give similar effects-as the control member described hereinafter that is, the fuel would be supplied under high pressure and it would be I9, which is parallel to the main passage 4L;

The heat container I9 is supplied with a removable bottom 44. The fuel line I8 is inserted through a hole in the removable bottom 44, wound into several coils, inserted in the heat container I9 with end extending through the hole in the upper part of it. The removable bottom is then pressed in the heat containerand welded at its edges. The openings around the fuel line I8 at the entrance and exist of heat container are also welded so as to prevent leakage. The two passages, 42 and 43, c nnecting the main passage II and the heat ccatainer I9, are supplied with valves 26 and 21 which operate simultaneously and-shunt the desired quantity of the exhaustgas through the heat container and thus heat the fuel in the coil l8 and also control its temperature.

After passing through the heating device the fuel continues through fuel line I8, fittings 45 and 48, Figure 4, and into reservoir 41 of the carburetor body I. The fuel then passes through channel 48 which has the control member 6 placed in it so as to control the flow through it. The control member 8, Figure 5 is shown as a barrel type valve with a hole' 49 j drilled in it. It is held in place, so that hole 49 mate with channel 48, in the drilled hole 58 by screw 59 which fits in the annular groove in it; it isoperated by lever 5'which is attached to it by pin 5|. By rotating-the control member 6 though an angle of about 90 the flow of fuel orifice ll into the air stream, caused by suction of pistons, flowing into the intake manifold 2. The opening between the needle valve 56 and orifice l l determines the degree of atomization .and due to its size tends to keep the flow through it steady. The degree of atomization can be adjusted by means of screw 51, Figure 4, held by thimble 58 which is seated by threaded engagement in the body I and against the nozzle 53 which is againsta shoulder in the body i.-'

The needle valve 55 is held at the lower end against a screw 51 by the fuel pressure. The small tapered projection on the needle valve is very important as it determines the spray angle and fineness of the spray of fuel injected into-the airstream.

The fuel nozzle 53 is set at an angle in the" body so as to keep the air stream from blowing the spray of fuel against the rear of the body I.

The air stream, caused, by the suction of the pistons in the engine 3, enters the mouth of the carburetor by the throttle valve l0, passes the nozzle 53 which sprays fuel into it, and enters the intake manifold 2. The throttle valve 1' allows sufilcient air to enter. for best mixture with fuel at low outputs of the enginefbut the throttle valve I0 is wide open when the control member 6 is approximately half open., Due to the very small quantities .of fuel. necessary at low power outputs and idling, the air must be throttled so as to obtain the air-fuel ratio. From half to full outputs of the engine,-the throttle valve remains wide open and thus offers no resistance to the flow of air. Fuel is simply supplied by pressure to the air stream, in proper proportion, by the control member 6 from halfto full outputs of the engine. present types of carburetors in that the air is not restricted or controlled, except at low power output, but is allowed to enter uncontrolled and fuel is simply forced into it in an atomized form, in proper proportion. This gives higher volumetric efiiciency and thus better operation.

Thus a. means has been described in which fuel under pressure is positively controlled, atomized, vaporized, and injected into the airstream entering an internal combustion engine.

To facilitate the best operation of the above.

means, supplementary means have been provided so as to maintain a practically constant pressure on the fuel being supplied to the orifice for both the intake and discharge strokesof the highpressure plunger pump l6 and so as to held by thimble 62, which is screwed in the' body I. On the discharge stroke of the pump l5 thew spring BI is compressed but on'the intakestroke the spring 5| expands and thus keeps a practically constant pressure on thefuel and control member for both intake and discharge strokes of the pump Hi. If the fuel pressureis not held constant, for a certain speed, the re-' sult be that the fuel will not be supplied This differs from to the air stream steadily, that unequal chargeswill enter the cylinders, and that operation will be irregular. The object of this method of carburetion is to thoroughly mix the proper proportion of. fuel with air. It can be readily seen that the supply of fuel should introduced at a steady rate for best mixture at any speed.

\Thepump it was designed to givesufilcient fuel at full power output of the engine. This is more fuel than required at lower outputs so I have provided a means which bypasses the toward the bottom of the carburetor body 'I thus I compressing the spring ii. The spring 6|. is compressed until the end of the valve 53 touches the pressure adjusting screw 54, which is screwed in thimble 62 and locked by nut 65. If there is a further increase in pressure, after the end of the valve .63 touches .the pressure adjusting v screw 64, it will force piston further and thus open valve 63 against spring 86 and allow fuel to be bypassed, until pressure drops, through channel 61, fitting 68 and into fuel line 28. The

screw 64 is adjustable in thimble 52 so as to'give most any desired pressure of the fuel.

Having thus described my inventiomwhat I claim as new and desire to secure 'by Letters Patent is:

1. A carburetor for an internal combustion engine comprising, a mixing chamber, means for supplying an unrestricted stream of air to the mixing chamber, means for injecting fuel under pressure into the air stream. means for preheating said fuel before injection, "spring operated means for maintaining a constant pressure of the fuel injected,-and a spring actuated valve coacting with said spring operated means for by-' passing the fuel whenever the pressure becomes excessive.

2. A carburetor for an internal combustion'engine comprising, a body having an unrestricted enlarged air passage extending therethrough and free from ports at each end, whereby the suction of the motor may .draw a. steady volume of air through the passage without reducing it into a plurality of air streams, a mixing chamber in' said passage intermediate the ends thereof,

meansfor injecting 'fuel'into the volume of'air 1 passing through the mixing chamber, means for positively controlling the quantity of fuel injected, whereby a proper mixture of fuel and air is obtained, means for heating the fuel before injection, a spring-pressed piston for maintaining a constant pressure of the fuel injected undernormal conditions, and a spring loaded valve carried by said piston for by-palssing the fuel when the pressure becomes excessive. I

3. A carburetor for an internal combustion engine comprising, a mixing chamber, a fuel supply tankconnected with the mixing chamber, a

nozzle in the connection and open to the chembet, means for injecting fuel under pressure through the .nozzle intothe air stream through said chamber, a sprlng-operatedjpiston inthe connection between the tank'and nomle for maintaining a constant pressure of the fuel.

injected, and a spring loaded valve carried by said V piston for by-passing the fuel back-to'the when the pressure becomes excessive.

' 4. A carburetor for an internal combustion engine including, a mixing chamber, means for supplying an unrestricted stream of air to the tank mixing chamber, means for injecting a fuel under pressure into the air stream passing through the mixing chamber, a. piston subjected to the fuel pressure injected into the chamber, a spring exerting its pressure against the piston for maintaining the pressure of the .fuel constant, and a spring loaded valve carried by the piston for by-'-' passing the. fuel when the pressure thereof-becomes excessive.

5. A carburetor for an internal combustion engine including, a mixing chamber, means for supplying an unrestricted stream of air to the mix,

ing chamber, means for injecting a fuel under pressure into the air stream passing through the mixing chamber, a piston subjected to the fuel pressure injected into the chamber, a spring exerting its pressure against the piston for maintaining the pressure of the fuel constant, a spring loaded valve carried by .the piston, and means -for engaging the valve for opening said valve to :Iecting fuel into said air stream in said chamber, means for positively controlling the quantity of fuel injected into said .air stream, whereby a proper mixture of fuel and air is obtained, spring inlet of the mixing chamber, and a connection between said valveand the control means for the fuel quantity, whereby upon initial movement of said fuel control means the control valve is operated relative to the operation of said fuel control means, and-after said fuel control means has reachedhalf throttle the valve iswide open, thereby providing an unrestricted air inlet while said fuel control means is moved from half to full throttle. g

7. A carburetor for an internal combustion engine including, a housing, a mixing chamber in the housing, means for supplying. air to said chamber, .a fuel receiving chamber in the housing, the housing having a passage connecting the fuel receiving chamber and the mixing chamber, means for introducing fuel under pressure into the fuel receiving chamber, spring actuated means within said receiving chamber for maintaming a-constant pressure of the fuel being forced through the passage into the mixing chamber, and a spring loaded valve co-acting with said spring actuated means for by-passing the fuel from the receiving chamber when the pressure of said fuel becomes excessive.

n. RAVANELLl. 

